Self locking threaded connector

ABSTRACT

A self-locking threaded connection including an externally threaded male part having a series of projections adjacent the trailing or last-to-be-threaded threads and an internally threaded female part having a series of detents adjacent the leading or first-to-be-threaded threads. As the parts are threaded together, the snap reception of the projections into the detents produce both audio and tactile responses indicating that the connection is made and near to a destructive over tightening.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-in-Part of U.S. Ser. No. 10/891,399 filed Jul. 14, 2004.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT NONE REFERENCE TO A “SEQUENCE LISTING”

Not applicable.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates generally to a threaded connector, and more particularly but not by way of limitation, to a threaded connector that is self-locking as may be used either alone, or in combination with plumbing fixtures including but not limited to plumbing pipes and in particular to plumbing pipes subject to vibration such as garbage disposal drains and the like.

2. Description of Related Art

Manufacturers have long used various sorts of connections to assure a tight connection that can be undone if necessary, especially in the plumbing industry. Often two pipes are joined together permanently using piping dope or other forms of permanent adhesive that effectively form a plastic “weld”. These sorts of connections are quick and easy to make and do not require the exact tolerances that may be required for threaded connections. A disadvantage of this type of connection is that it is permanently welded in order to prevent fluid leaks. Thus, when there is a need to repair the plumbing, the connecting pipes must be cut.

Alternatively if the plumbing connection is a threaded connection, gaskets, doping materials or other nonpermanent fluid sealing agents may be employed to assist the threads in making a fluid tight joint. A threaded connection is easily undone to make a repair or to replace one or more plumbing components or fixtures. Threaded connections often use a top lip to hold one pipe against another pipe often with the help of a gasket. However, even when there are in no internal pressures, as in a drain line, it may be difficult to make a threaded connection that effects a fluid tight seal and maintains a fluid tight seal over time.

This is particularly the case if the plumbing is subjected to vibration, such as the drain from a sink drain, garbage disposal or dishwasher. In such cases the threaded connection may become loosened over time allowing leakage. Hence, plumbing connections in such situations are often over tightened in the attempt to make a tight seal. As it is not uncommon for drains such as sink drains and the like to be formed of plastic (such as PVC), over tightening may result in fractured or broken parts. Over tightened joints are also not easily disassembled or undone when needed. The following invention overcomes these problems by providing a threaded connector that is self-locking when the proper seal connection is made. The self-locking feature makes it very difficult to over tighten a plumbing connection that needs to be fastened to a specific tightness and allows ease of disassembly to undo the connection.

BRIEF SUMMARY OF THE INVENTION

The present invention includes components of a threaded connection, including a male part having external threads and a female part with internal threads. The male part has one or more protrusions located such that when the female and male parts are mated together in a proper sealing relationship, the protrusions on the male part mate with and releaseably lock into recesses on the female part to resist loosening of the threaded joint.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

FIG. 1 is a front elevation view partly broken away and in section showing components of the self lock threaded coupling of the present invention prior to assembly;

FIG. 2 is a side elevation view of the coupling partly broken away and in section showing the coupling as assembled;

FIG. 3 is an end view of the female part of the coupling;

FIG. 4 is a view taken generally along lines 4-4 of FIG. 2;

FIG. 5 is an elevation view, partly broken away and in section showing another embodiment of the invention;

FIG. 6 is a sectional view taken generally along lines 6-6 of FIG. 5; and

FIG. 7 is a cross sectional view of the male member showing another embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring to the drawings, FIG. 1 shows the coupling of the present invention generally indicated at 10. The coupling includes a male part 12 comprising a pipe section 14 having exterior threads 16 at one end and a female part 18 having internal threads 20. The female part 18 is threaded to the external threads 16 on the male part male part so as to couple an unthreaded pipe section 22 to the pipe section 14.

In this respect the unthreaded pipe section has a flat flange 24 that is engaged by a collar 26 on the female part and pressed against an end face 28 of the male part upon threading the male and female parts together (see FIG. 2). Such a connection is common in plumbing fixtures such as in sink drains and the like.

Plumbing connections of the type described are not usually employed in situations where there is an internal pressure. Accordingly, making the connection finger tight usually is sufficient to prevent leakage through the joint. In some cases a gasket (not shown) is inserted between the flange 24 and the end face 26.

The male part 12 has an entry thread portion 30 on a leading end and a trailing or last-to-be-engaged thread portion 32. Adjacent the trailing thread portion 32 on the male part are a series of projections 34, preferably three in number. The projections preferably are generally spherical and can either be fixedly imbedded into the wall structure of the male part or formed integral the wall structure. In either case the first two projections 34A and 34B are just in advance of, or lead, the trailing thread portion 32 in the direction of rotation (Arrow A) while at least one projection 34C just trails or lags the trailing thread portion 32.

The female part 18 has an entry lip 36 and the leading thread portion 38 of the female part starts slightly inboard of the lip. The trailing or last-to-be connected female thread portion is identified at 40. As best seen in FIG. 3 the lip has a constant outside diameter. However the lip has a section indicated at 41 that is thicker than the remaining portion of the lip. This thicker section 41 is formed by a decrease in the inside diameter of the lip. Formed in this thicker section 41 is a series of spaced detents 42, preferably four in number. These detents include detents such as 42A and 42B that are in advance of the leading thread portion 38 in the direction of rotation (Arrow B in FIG. 1) while others such as detents 42C and 42D are alongside or over lap the leading thread.

Accordingly, it should be appreciated that when a threaded connection is made, the detents 42 in the lip 36 of the threaded female part 18 pass over the entry thread portion 38 on the leading end of the male part. The threading continues unimpeded until the entry thread portion 30 of the female part approaches the trailing or last-to-be-engaged thread portion 32 of the male part. As the entry thread 38 of the female part nears the male trailing thread 32, the first projection 34A begins to encounter the thicker section 41 of the lip.

As finger tightening continues, the first projection 34A starts to bind against the inside surface of the lip at the thicker section (because of the decrease in the inside diameter) and then snaps into the first detent 42A. The snapping of the projection into a detent produces an audio response as well as a tactile sensation that the user can “feel”, both indicating that the coupling is close to being made.

As tightening continues still further, the first projection 34A is forced out of the first detent 42A and over into the second detent 42B while the second projection 34B first encounters the thickened setion 41 of the lip and then enters the first detent 42A. With two projections bearing against the inside surface of the lip, the force required to tighten the coupling increases. This increase in the force needed to tighten the coupling as well as the tactile response each time a projection enters a detent cooperate to let the user know that the point is being reached where there is a danger of over tightening the coupling.

Tightening the coupling still further forces the two projections 34A, 34B from their respective detents 42B, 42A and brings all three of the projections to bear against the inner surface of the lip 36. These increases still further the force required to finger tighten the male and female parts together. Eventually all three of the projections 34 will be captured in detents 42.

While in the embodiment as described the number of projections exceeds the number of detents, it should be appreciated that the number of projections and detents can be equal. Also, the positions of the projections and detents can be reversed. In this respect FIGS. 5 and 6 show projections 50 extending inward from the inner periphery of the lip 36 in advance of the leading threads 38. In this embodiment the male part 12 has a thickened section 52 on its periphery adjacent the trailing or last-to-engage thread 32. Formed in this thickened section are detents 54. As the lip 36 passes over the trailing threads 32 on the male part the projections 50 on the lip engage first one and then another of the detents 54.

FIG. 7 shows another embodiment of the invention showing how the projections, rather than being formed integral the male part, may be embedded into the wall of the male part. In this respect FIG. 7 shows that holes 60 are drilled through the wall 62 of the male part. Spherical elements 64 such as ball bearings or the like are placed into the holes, the diameter of the spheres being smaller than the diameter of the holes so the spherical elements don't fall through the holes. Then an adhesive such as an epoxy or the like is applied as shown at 66 to hold the spheres in place. In this embodiment the material of the spherical elements 64 preferably is harder that the material of the male and female parts. With this arrangement there is less wear of the projections when a coupling is made and this in turn allows for more repeated connecting and disconnecting of the coupling before the there is so much wear of the detents that the snap fitting loses its effectiveness.

Accordingly, as the pipe collar 24 and the end face 28 of the male part are brought together to make a junction as shown in FIG. 2, the force required to thread the male and female parts together is at a maximum. As noted above the capture of the projections can be both felt and heard as a “snap” so both tactile and audio signals alert the user that the male and female parts are close to being fully tightened and that further tightening may result in an over tightening of the parts to the point of damaging the threads on either the male or female parts. These tactile and audio signals provide cautionary signals in addition to the increase in the resistive force that is felt during the finger tightening. Also, since one or more of the projections 34 are captured in one or more of the detents 42, there is less of a likelihood of the coupling being separated by vibration. 

1. A threaded connector comprising: a) a male part having external threads including an entry thread portion on a leading end of the male part and a trailing thread portion; b) female part having internal threads extending along the female part including a leading thread portion and a trailing thread portion, the male and female parts being screwed together finger tight to effect a seal at the leading end of the male part; c) the female part having an unthreaded lip in advance of the leading thread portion; d) cooperating members on the lip and male part trailing thread portion, the cooperating members engaging one another upon a seal being effected at the male member leading end; and e) the cooperating members comprising means for preventing the over tightening of the male and female parts and for preventing vibration induced loosening of the male and female parts.
 2. A threaded coupling as in claim 1 wherein the engagement of the cooperating members provides an audio signal indicating the approach of thread damaging over tightening.
 3. A threaded coupling as in claim 1 wherein the engagement of the cooperating members provides a tactile signal indicating the approach of thread damaging over tightening.
 4. A threaded coupling as in claim 1 wherein the cooperating members include a projection adjacent the trailing thread portion of the male part and a detent in the lip of the female part.
 5. A threaded coupling as in claim 4 wherein the lip has a constant outside diameter and a thickened section formed by a variation in the inside diameter of the lip, the detents being formed in the thicker section of the lip.
 6. A threaded coupling as in claim 4 wherein the number of detents exceed the number of projections.
 7. A threaded coupling as in claim 4 wherein a wall of the male part has at least one hole and the projection on the male part is a spherical element inserted into the hole, the diameter of the spherical element being greater than the diameter hole.
 8. A threaded coupling as in claim 7 wherein the material of the spherical element is harder than the material of the female part.
 9. A threaded coupling as in claim 1 wherein the cooperating members comprise: a) at least one projection on the female part in advance of the leading thread portion of the female part; and b) the male part has a thickened peripheral portion adjacent the trailing thread portion of the male part and at least one detent formed in the thickened peripheral portion for receiving the projections upon the male and female parts being threaded together.
 10. A self locking threaded connector comprising: a) a male part having external threads and an end face; b) a female part having a leading edge and internal threads extending along the female part from the leading edge, the screwing together of the male and female parts effecting a seal at the end face of the male member; and c) cooperating lock members on the male and female parts, the external threads being intermediate the end face and the locking member on the male part and locking member on the female part being generally along the leading edge and the members being in locking engagement upon the threading of the male part into the female part to a sealing position.
 11. A self locking threaded connector as in claim 10 wherein the cooperating lock members comprise at least one projection on the male part adjacent a trailing and last-to-be engaged external thread and a detent on the female part in advance of a leading and first-to-be engaged internal thread.
 12. A self locking threaded connector as in claim 11 wherein the number of detents exceeds the number of projections by one.
 13. A self locking threaded connector as in claim 10 wherein the cooperating lock members includes a plurality of projections on a lip of the female part in advance of a leading and first-to-be-engaged internal thread and at least one detent formed in a thickened section of the male part adjacent the trailing and last-to-be-engaged external thread.
 14. A self locking threaded connector as in claim 13 wherein the number of detents is at least equal to the number of projections.
 15. A self locking threaded connector as in claim 11 wherein a wall of the male part has at least one hole and the projection on the male part is a spherical element inserted into the hole, the diameter of the spherical element being greater than the diameter hole.
 16. A threaded coupling as in claim 15 wherein the material of the spherical element is harder than the material of the female part. 